TRANSLATOR’S PREFACE 
Rignano is a student of Biology who has also the 
training of an engineer and physicist. His attack on bio- 
logical problems is from that side. In this book he offers 
an explanation on a physical basis of assimilation, cell di- 
vision, and the biogenetic law of recapitulation in ontog- 
eny, and he suggests a mechanism whereby the inheritance 
of acquired characters may be effected. 
Such a study of the most fundamental and difficult of 
biological problems can not fail to be of the greatest in- 
terest to all students of science. It points out a way to 
the understanding of the essential nature of living matter. 
Therefore the translator has gladly consented to prepare 
for publication this translation first made for his own sat- 
isfaction. It has been revised by the author. 
University of Chicago, 1911. 
Basi, Harvey, 
